This invention relates to novel N-aryl-3-aryl-4,5-dihydro-1H-pyrazole-1-carboxamides which are useful as pesticides, compositions containing those compounds, methods of controlling pests and processes for preparing the compounds of the present invention.
The search for pesticides which have a combination of excellent pesticidal activity and essentially no toxicity is a continuing one due to recognition of the possible toxicity to animals and humans of many known pesticides.
Certain pyrazoline derivatives have been disclosed as having insecticidal activity.
German Offenlegungsschrift No. 2,304,584 discloses pyrazoline compounds which are substituted in the 1,3 or 1,3,5 positions of the pyrazoline ring that exert biocidal activity. German Offenlegungsschrift No. 2,304,584 corresponds to U.S. Pat. Nos. 3,991,973; 4,095,026; and 4,101,271.
U.S. Pat. Nos. 4,156,007; 4,070,365; and 4,174,393 disclose pyrazoline compounds which are substituted in the 1,3 and 4 positions of the pyrazoline ring that have insecticidal activity.
U.S. Pat. Nos. 4,140,787 and 4,140,792 disclose pyrazoline compounds which are substituted in the 1,3,5 positions of the pyrazoline ring that possess arthropodicidal properties.
Presently known compounds are believed to be subject to problems with photostability and biodegradability. These compounds tend to degrade faster than is desirable when applied to the external parts of plants due to the action of sunlight on these compounds. Moreover, when known compounds are applied to the soil, they exhibit poor biodegradability causing an undesirable residue to remain in the soil.
The present invention discloses N-aryl-3-aryl-4,5-dihydro-1H-pyrazole-1-carboxamides (hereinafter at times referred to as 1-substituted-4-substituted-4,5-dihydro-1H-pyrazoles), including N-aryl-3-aryl-4,5-dihydro-1H-pyrazole-1-thiocarboxamides and including N-aryl-3-aryl-4,5-dihydro-1H-pyrazole-1-iminocarboxamides which are disubstituted at the 4 position or monosubstituted at the 4 position. When these compounds are monosubstituted at the 4 position, the substituent has, at the 4-position, 1-oxo, 1-thiono, 1-imino or 1-alkenyl functionality.
It is believed this 4,4-disubstitution greatly lessens photodegradation and metabolic pathway transformations in plants and insects by blocking hydrogen loss and subsequent aromatization of the dihydropyrazole moiety to a pyrazole moiety resulting in an inactivation of the compound as an insecticide.
Certain of the compounds, particularly the 4-carboalkoxy substituted compounds (4-monosubstituted and 4-disubstituted) of this invention exhibit enhanced rates of soil metabolism thus minimizing undesirable residues.
It is therefore an object of the invention to provide novel compounds, and compositions containing said compounds, which possess pesticidal activity. It is another object of the present invention to provide compounds which demonstrate improved photostability and biodegradability. It is a further object of the invention to provide methods for the synthesis of 1-substituted-4-substituted-4,5-dihydro-1H-pyrazoles.
It is still another object of the present invention to provide methods for controlling pests and insects using the novel compounds.
These and other objects of the invention will become apparent to those skilled in the art from the following description.